The Mystery Jet! <br><br>Post edited by: Roadkill1962, at: 2006/08/21 03:07

OK...that was funny...I was worried I couldn't upload a pic, and the pic was all that came through! No text! Let me try this again...

Greetings, all...I've enjoyed reading all your posts, and have been reading every tech tip here that I can. And let me apologize in advance for what will be a LONG first post for me. I've been a member of the R* Clinic for almost a year in anticipation of getting one when the perfect bike came along at the perfect time. Well, that happened in June...it was a trade-in at a Harley dealer, and since no respectable Harley dealer wants a Yamaha on his lot, they were itching to get rid of it fast...and cheap. SO, I'm now the PROUD owner of a 2004 (only 4,100 miles on it!) Pearl White R*, and damn happy about it.

Anyway, here's my situation. The bike has been running fine (sort of), but mileage has been terrible...MAYBE 30 MPG. All I knew about the mods the previous owner might have done was the set of Cobra slash cut slip-ons I could see on the bike and a little extra chrome here &amp; there.

One thing I noticed is that when I stuck my hand down at the very end of the exhaust, the front cylinder was firing like POP-POP-POP, but when I held my hand by the rear cylinder exhaust, it was more like POP......POP......POP. About half as many firings as the front cylinder. I did some work on the bike this weekend, and it still does it, even with 4 new plugs. I'll come back to all that I did in a second.

Back to the (lack of) MPG...From reading posts here, I knew the MPG was WAY below where it should be. So, I figured I was running rich since the bike came from Phoenix (near sea level) up here to N. New Mexico (5,900 feet) and had a stock airbox on it, and it just was getting too much fuel and less air courtesy of altitude.

So, despite my better judgement, I decided to tear into the bike this weekend and see what was what.

Here's what I did (thanks to this forum's Tech Tips--I have the Yamaha Service Manual, but found myself referring to Tech Tips I printed out FAR more than the manual!):

1 - Removed stock airbox &amp; replaced it with a Yamaha Speedstar K&amp;N filter setup on stock airbox backplate. The hose inside the airbox that used to be hooked to the nipple on the stock air filter is still in there...hooked to nothing. Problem?

2 - Rejetted carb with a Dynojet kit-- DJ 175 main, DJ pilot, clip on #4, PMS 2.75 turns out. The vacuum breather hose (with the little black canister) on top of the carb is (and was before all this) hooked to nothing. Problem?

3 - Removed AIS and installed port cover plates w/thread locker. Capped manifold vacuum intake.

4 - Installed 4 new plugs.

Now, what got me was the carb jetting (this is the mystery part I mentioned)...like I said, I've read tons of tech tips here, so I expected the carb to be stock when I saw the brass plug over the PMS was still intact. But when I took off the float bowl cover, I didn't see a &quot;165&quot; or anything similar...it's stamped &quot;182.5&quot; and has a capital &quot;R&quot; on it followed by some symbol. If it was a DJ jet, 182.5 is NOT stock ant still too big if it was. I don't even think DJ makes that size. And if it's a Mikuni, using the conversion chart I found here that makes it equivalent to a DJ 194.7!!! I'll try to include a pic, but any ideas? And I don't know what a stock needle looks like, but this one only had one slot for the clip and was not nearly as tapered as the DJ.





Now it runs, but it sounds like it's missing whereas it didn't before...almost like timing is off. I think I read that missing=too lean and sputtering=too rich...? I don't think my settings are on the lean side. The missing is noticeable at idle, Pronounced at 1/4 throttle, and noticeable above that, but MAYBE not as much (all done sitting in the garage...&quot;field test&quot; cancelled due to thunderstorms &amp; floods).

And it still does the popping thing where the back cylinder sounds like it's firing 1/2 as much as the front cylinder. The plugs I took out were all BLACK {that pic of the rear plugs wasn't lighted any differently than the front plug pic...they really are that black!) after no more than 4,100 miles...that mean too rich?

I dunno. All help &amp; suggestions is &amp; are welcomed. And it feels good to post something finally. I promise they'll be shorter from now on!

TIA,

Scott<br><br>Post edited by: Roadkill1962, at: 2006/08/21 03:00

I'm definitely doing something wrong here...but i think I figured out the pics...<br><br>Post edited by: Roadkill1962, at: 2006/08/21 02:57

Welcome Roadkill

I haven't jetted mine (Yet) but from what I've read those are stock parts. To me the mystery is why they put the 182 in there. The needle is another reason why people re jet.

Thanks, Musky...it's a mystery to me, too. Seems like a big jet...and why change just that?

Anyway, if it would just stop raining here long enough for a ride, I'd take the bike out for a road test. It felt REALLY good to work on an engine again. Last time I did that, I pulled an old Chevy 283 out of the junkyard and rebuilt it from the ground up...but that WAS 25 years ago. This is the first bike I've owned, but I learned a heckuva lot about it this weekend. I can't wait to do more!

Since it's a carbed motor, I'm GUESSING the R* has some sort of a distributor...? Maybe points are bad, rotor perhaps, or maybe just a bad spark plug wire...but that's my &quot;old school&quot; automotive experience talking...LOL

RK

Roadkill wrote:
Since it's a carbed motor, I'm GUESSING the R* has some sort of a distributor...? Maybe points are bad, rotor perhaps

The roadies have an ignition box.

The 04 came with a Mikuni 182.5 main; the pre-04 came with the Mikuni 165. That's also the stock needle in your pic but one washer is on the wrong side of the clip and the white spacer is missing.

The settings you now have are pretty close to where it should be (DJ 175 main, DJ pilot, clip on #4, PMS 2.75 turns out) except I don't know what the size of the pilot.

I assume that the clip is on 4 from the top (blunt end) and that the order from the top is washer, clip, white spacer, washer?

It could still be running back due to carbon build-up so I would recommend that you first try using Marvel Mystery Oil, Yamaha Ring Free, Seafoam or another equivalent. You can do a shock treatment but be sure to change the oil after one tank.

To answer your more specific questions:

1. “The hose inside the airbox that used to be hooked to the nipple on the stock air filter is still in there...hooked to nothing. Problem?”

The stock backplate has a nipple on the outside to which the crankcase vent hose is hooked up. The small hose on the inside goes to the backside (inside) of this connector.

2. That hose does not go anywhere. It just vents to the atmosphere.

Doc

Thanks Doc!

The spacer from the needle is missing because I used it on the new needle (per DJ instruction sheet). The order on the new DJ needle (from the top/blunt end) is: washer, clip on #4 from the top/blunt end, white spacer from stock needle. The DJ sheet said not to use the washer below the spacer.

The hose in the airbox is connected to the nipple inside the box, running out to the crankcase hose on the outside of the box and down to wherever it was originally connected. I just didn't know if I should cap that off inside the airbox where it used to go to the filter, but I'm GUESSING not. Even crankcases gotta breathe, no?

I remember reading your response to someone else regarding the Marvel Mystery Oil treatment, so I can give that a try (if they carry it at our local Autozone). I remember seeing reference to Ring Free and the shock treatment in posts somewhere, but I'm not sure what they are. I'll read up. Are they things that have to be done separately, or can they be combined (i.e. shock AND Marvel at same time)?

Good thing I didn't get to changing the oil this weekend...sounds like I'd just need to do it all over again... BTW, I picked up 5 qts. of Shell Rotella 5W/50 full synth oil, no friction modifiers because of the wet clutch (see? I HAVE been reading a lot here! ). I saw a number of posts here recommending that oil...did I get it right?

Thanks again for all your help everyone--

RK

You did good .... except the color of the bike .... it's not red

Put one washer under the white spacer. I think I read somewhere that the needle may 'stick' without it.

No, don't cap it off inside if you have the outside black hose connect. You need to vent the carnkcase, but you don't have to connect the crankcase breather hose to the back of the aircleaner; you can re-route it down under the bike or to a filter (like Krankvent). I didn't like the oil re-circulating through my aircleaner and carb so I re-routed mine. I find that it's much less oily now.

All those products are equivalent in purpose so use one or the other, or whatever else you can get in your area. MMO is just easier for me to buy .... and cheap.

I've found Valvoline 5W50 too wide of a range for me. I found the bike ran noiser than when I use the Mobil 15W50. Try it out and see out it runs for you.

doc

Doc wrote:
You did good .... except the color of the bike .... it's not red

It's all envy Roadkill. Everyone knows white is the fastest color.